beginner swimmer | lacking coordination | need help

Hello All, I am taking swim instructions through the local USMS ALTS program. it is a new program where adults are given swim instructions. I am in my early 50's and just never till now. I am in the 4th week of my lessons and seem to have (mostly) overcome the fear of water =). We are now at the part of the instructions where we are learning freestyle swim and that's where I am at a complete roadblock. I am unable to co-ordinate my feet/legs movement with the arms. I can hold my breath and move my feet/legs and do just fine for several feet in distance but the second I start using my arms, my feet/legs stop. Its one of those cliche's about unable to walk and chew gum at the same time, while I say that in a lighthearted joke, I am feeling very frustrated with this issue and feel that I won't be able to proceed with the next phase of the lessons where I learn how to move my head side to side and breathe. Is this common (unable to coordinate legs and arms)? I am open to ANY suggestions/advice/suggestions from you to help overcome this mental block. all feedback is welcomed and appreciated. Thank you XMFan